Compensating turntable drive



fume 3, 1941. V E y SCHNEIDER 2,244,12Q

COMPENSATING TURNTABLE DRIVE Filed Feb. 8, 1941 2 sheets-sheet"! I I I J1me 1941- E. v. SCHNEIDER 2,244,120

- COMPENSATING TURNTABLE DRIVE Filed Feb.'8, 1941 2 Sheets-Sheet 2 I 35mm Zia/1101' Zlfl'izeidg/ Patented June 3, 1941 COMPENSATING TURNTABLE DRIVE Emmor V. Schneider, Alliance, Ohio, assignor to The Alliance Manufacturing Company, Alliance, Ohio, a corporation of Ohio 4 Application February 8, 1941, Serial No. 377,988

6 Claims.

The invention relates to phonograph turntable drives of the general character disclosed in my co-pending application Serial No. 294,938, filed September 14, 1939, and more particularly to a compensating drive so constructed that it will operate the turntable at a uniform speed,

throughout the entire recording or reproducing of a record, the present application pertaining to a further development of the invention disclosed in my co-pending application for Compensating turntable drive, Serial No. 366,056, filed November 18, 1940.

There has developed, in recent years, a growing demand for combination recording and reproducing phonographs for home use, such phonographs being relatively inexpensive, and.

provided with an induction motor, for economic reasons.

It has been found by experience, however, that turntable drives operated by such inexpensive motors are not entirely satisfactory because the motor does not have suflicient power to drive the turntable at a uniform speed from the start to the end of a record, especially in recording, and the turntable is driven more rapidly when reproducing than when recording.

Experience has shown that in recording upon such phonographs as are now in general use for home recording and reproducing, there is a differential of approximately eighteen inch ounces to six inch ounces between the start and the end of the record.

This results in noticeable variations in both the tempo and pitch of recordings made upon such phonographs.

It is also well known that there is a difference of approximately four revolutions per minute between the recording and the reproducing of a record upon inexpensive phonographs now in use.

Furthermore, due to the type of motor used for the turntable drive upon such phonographs, there is another objection to present practice phonographs of this type in the pulsations or v vibrations of the motor which arereproduced to.

a greater or less degree in the record.

It is, therefore, the object of the present improvement to provide a compensating turntable drive which will overcome the abovementioned' objections and provide for a uniform speed of recording and playing of records and minimize the pulsations or vibrations of themotor.

A further object of the invention is the provision of such a turntable drive in which the turntable is frictionally driven by a friction wheel,

upon the shaft of which is slidably mounted a second friction wheel contacting a tapered pulley on the motor shaft and arranged to move longitudinally relative thereto, to' compensate for variations in the speed of the turntable between the start and end of a recording. or between the recording and reproducing of a record.

Another object is the provision of such a turntable drive in which the slidably mounted fric-.

tion wheel is connected to the other friction wheel upon the shaft, by means of a torsion spring through which the drive is effected, whereby the pulsations and vibrations of the motor will not be reproduced in the recording or playing of a record.

A further object of the invention is the provision of a turntable drive of the character mentioried in which the slidable friction wheel is moved longitudinally, relative to the conical pul- 1e3 by means of a continuous helical rib or thread having a sufiiciently steep pitch to accomplish the desired result.

The above objects together with others which will be apparent from the drawings and following description may be attained in various manners by which a slidably mounted friction pulley is moved relative to a tapered friction'pulley upon the motor shaft with means for alternately moving the slidably mounted friction pulley to compensate for drag upon the turntable, and for the purpose of illustration, two forms of the invention are shown in the accompanying drawings in which- Figure 1 is a vertical sectional view through a phonograph turntable drive embodying the invention taken as on the line l--l, Fig. 2;

Fig. 2, a fragmentary plan section of the turntable drive shown in Fig. 1;

Fig. 3, an enlarged longitudinal sectional view through the shaft of the friction wheels and associated parts;

Fig. 4, a vertical sectional view through a phonograph turntable drive showing a slightly modified form of the invention taken as on the line 4'4, Fig. 5; v

Fig. 5, a plan sectional view onthe drive shown in Fig. 4; and

Fig. 6, an enlarged longitudinal sectional view of the frictional wheel shaft and associated parts shown in Figs. 4 and 5.

Similar numerals refer to similar parts throughout the several views.

The general assembly of the turntable drive may be quite similar to that disclosed in my cope'nding application Serial No. 294,938, filed September 1-4, 1939.

pressure of the needle upon the record ofiers resistance to the rotation of the turntable, the

carried by the bracket H which is fixed to the slidable plate Hi.

The slidable plate I 8 is mounted for sliding or swinging movement upon the motor mounting plate l9, which is supported upon the platform III as by the rubber grommets 20.

A downturned lug 2-| may be formed upon the slidable plate for sliding movement within the slot 22 in the motor mounting plate I 9.

A spring 23 being connected to the slidable plate I8 and the motor mounting plate |9 at opposite ends to urge the tire of the friction wheel l4 intofrictional contact with the rim l3 of the turntable. v

Sliding movement of the plat I8 is limited by means of the screw '24 threaded into the motor mounting plate l9 and located through the enlarged aperture in the slidable plate I 8, a flanged washer 26 spacing the head of the screw so as not to bind the slidable plate |8 and at the same time covering the enlarged opening 25.

The motor'may be of the usual induction type as indicated generally at 21 and is suspended as by the rods 28 from the motor mounting plate IS. The motor shaft 29 has an inverted conical pulley 30 fixed thereon.

The tubular shaft 3| is -journaled upon the stud |5,-a'nd the hub H of the upper or fixed friction wheel is shrunk or otherwise fixed upon said tubular shaft, and swedged in the wheel 33.

The lower portionof the tubular shaft 3| is screw threaded or provided with a helical rib 3|, and. the elongated hub 32 of the lower or movable friction wheel 33 is internally threaded, as at 34, to receive said helical rib or thread, so that the wheel 33 may be moved longitudinally upon the shaft.

The movable friction pulley 33 contacts the conical friction pulley 30 upon the motor shaft, and a torsion spring .35 is connected at one end to the wheel .33 as indicated at 36 and at its other end to the tubular shaft 3| or wheel H as indi-' cated at 31 whereby the friction wheel 3-3 willdrive the tubular shaft and wheel l4 through the torsion spring 35.

An upper stop 38 .is formed upon the hub IA of the upper or fixedv friction wheel, for engagement with the stop face 40, upon the upper end of the elongated hub32, and the lower stop 39 is formed upon the collar 4| for engagement with the stop face 42 at the lower end of the hub 32.

- The collar 4| is shrunk or otherwise fixed upon the lower end of the tubularshaft 3|, and

the entire assembly is held upon the stud H. by means of a washer 43 and a hair pin cotter pin 44 on the lower end portion of the stud.

In the normal position of the pants, as shown spring will be wound up rotating the movable friction wheel 33 upon the tubular shaft 3| in a direction whereby the screw threads 3| cause the friction wheel 33 to move upward upon the shaft bringing the periphery thereof into contact with a large diameter of the conical pulley 30.

As this action takes place the slidable plate i3 may move, upon the motor mounting plate l'9, against the pull of the spring 23 permitting the axis of the shaft 3| to shift in order to compensate for the larger diameter of the conical pulley contacting the periphery of the friction wheel 33., v

In the slight modification of the invention shown in Figs. 4 to 6, inclusive, the general assembly is similar to that above described and illustrated in Figs. 1 to 3, inclusive.

The platform of the phonograph cabinet is shown at Illa and the turntable a is rotatably mounted upon the spindle I21. carried by the platform, the turntable being provided with the usual depending peripheral flange |3a arranged to be driven by frictional contact with the rubber or similar rim of the friction wheel Me which is fixed upon the shaft its journaled in a suitin Figure 1, the spring 35 holds the friction wheel .lower end of the conical pulley 30.

In the operation of the phonograph, as the ab'le bearing "is carried by the slidable plate His. This slidable'plate is mounted for sliding or swinging movement upon the motor mounting plate |9s which is supported upon the platform Illa as by the rubber grommets 20a, and a downturned lug 2's may be formed upon the slidable plate for sliding movement within the slot 222.

in the motor mounting plate, a spring 233 being connected to the slidable plate and to the motor mounting plate to urge the tire of the friction wheel |4s into frictional contact with the rim 3a of the turntable.

,Sliding movement of the plate |8a is limited by means of the screw 24s threaded into the motor mounting plate I an and located through the enlarged aperture 25a in the slidable plate is, a flanged Washer 268. spacing the head of the screw so as not to bind the slidable plate and at the same time covering the enlarged opening.

The motor 219. may be of the usual induction type and is suspended from the motor mounting plate as by the rods 28a, and the motor shaft 298. has an inverted conical pulley 30a fixed thereon.

The lower end portion-of the shaft I52 may be provided with the helical rib or thread 3's. upon which the elongated hub 32a of the movable friction wheel-33a is internally threaded as at 34a.

The movable friction wheel 338. contacts the conical friction pulley 30.v and a torsion spring 359, is connected at one end to the wheel 33a and at the other end to the shaft I58 whereby the friction wheel 33:! will drive the shaft |5a and Ma through said torsion spring.

A stop pin 385. may be fixed upon the shaft for engagement with the stop face 40a upon the upper end of the hub 32a.

substantially the same as above described.

I claim: a

1. A transmission including a driving means, a tapered friction roller operatively connected to said driving means, a yieldable mounting member, a shaft journaled upon said mounting memdriven means operatively associated with said friction wheel, a friction wheel movably mounted upon said shaft and frictionally associated with the tapered roller and torsion spring and screw ber, a driven means operatively connected to said shaft, a friction wheel movably mounted upon said shaft and frictionally associated with the tapered roller, and torsion spring and screw means connecting the friction wheel and the shaft for moving the friction wheel axially relative to the tapered roller to compensate for variations in drag and resultant speed changes of the driven means.

2. A transmission including a driving means, a tapered friction roller operatively connected to said driving means, a yieldable mounting-memsate for variations in drag and resultant speed means connecting the movable friction wheel and the shaft for moving the movable friction wheel axially relative to the tapered roller to compenchanges of the driven means, and means for limiting the axial movement of said movable friction wheel in each direction.

5. A transmission including a driving means,

a tapered friction roller operatively connected to ber, a shaft journaled upon said mounting member, a friction wheel fixed upon said shaft, a

driven means operatively associated with said friction wheel, a friction wheel movably mounted upon said shaft and frictionally associated with the tapered roller and torsion spring and screw means connecting the movable friction wheel and the shaft for moving the movable friction wheel said driving means, a yieldable mounting member, a shaft journaled upon said mounting member, a friction wheel fixed upon the shaft, a driven means operatively associated with the friction wheel, a second friction wheel threaded upon the shaft and frictionally associated with the tapered roller, stop means upon the shaft for limiting the movement of the second friction wheel in one direction, and torsion spring means connecting the axially relative to the tapered roller to compensate for variations in drag and resultant speed changes of the driven means;

3. A transmission including a driving means, a tapered friction roller operatively connected to said driving means, a yieldable mounting'member, a shaft journaled upon said mounting member, a friction wheel fixed upon said shaft, a driven means operatively associated with said friction wheel, a friction wheel movably mounted upon said shaft and frictionally associated withthe tapered roller, and torsion spring and screw means connecting the movable friction wheel and the shaft and controlled by torque upon the driven means for moving the movable friction wheel axially relative to the tapered roller to compensate for variations in drag and resultant speed changes of the driven means.

4. A transmission including a driving means, a tapered friction roller operatively connected to said driving means,.a yieldable mounting member, a shaft journaled upon said mounting member, a friction wheel fixed upon said shaft, a

second friction wheel and the shaft for urging said second friction whee] toward the stop means,

so that said second friction wheel is moved axthe tapered roller, stop means upon the shaft for limiting the. movement of the second friction wheel in one direction, and torsion spring means interposed between and connected to the two friction wheels for urging said second friction wheel toward the" stop means, so that said second friction wheel is moved axially relative to the tapered pulley by variations in drag to compensate for resultant variations in speed of the driven means.

EMMOR V. SCHNEIDER. 

